netdev - Re: [PATCH] net: stmmac: dwmac-rk: fix unbalanced pm_runtime

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Date:   Mon, 30 Aug 2021 22:49:32 +0900
From:   Punit Agrawal <punitagrawal@...il.com>
To:     Michael Riesch <michael.riesch@...fvision.net>
Cc:     wens@...nel.org, netdev <netdev@...r.kernel.org>,
        "moderated list:ARM/STM32 ARCHITECTURE" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>, sashal@...nel.org
Subject: Re: [PATCH] net: stmmac: dwmac-rk: fix unbalanced pm_runtime_enable
 warnings

Hi Michael,

Michael Riesch <michael.riesch@...fvision.net> writes:

> Hi ChenYu,
>
> On 8/29/21 7:48 PM, Chen-Yu Tsai wrote:
>> Hi,
>> 
>> On Mon, Aug 23, 2021 at 10:39 PM Michael Riesch
>> <michael.riesch@...fvision.net> wrote:
>>>
>>> This reverts commit 2c896fb02e7f65299646f295a007bda043e0f382
>>> "net: stmmac: dwmac-rk: add pd_gmac support for rk3399" and fixes
>>> unbalanced pm_runtime_enable warnings.
>>>
>>> In the commit to be reverted, support for power management was
>>> introduced to the Rockchip glue code. Later, power management support
>>> was introduced to the stmmac core code, resulting in multiple
>>> invocations of pm_runtime_{enable,disable,get_sync,put_sync}.
>>>
>>> The multiple invocations happen in rk_gmac_powerup and
>>> stmmac_{dvr_probe, resume} as well as in rk_gmac_powerdown and
>>> stmmac_{dvr_remove, suspend}, respectively, which are always called
>>> in conjunction.
>>>
>>> Signed-off-by: Michael Riesch <michael.riesch@...fvision.net>
>> 
>> I just found that Ethernet stopped working on my RK3399 devices,
>> and I bisected it down to this patch.
>
> Oh dear. First patch in a kernel release for a while and I already break
> things.

I am seeing the same failure symptoms reported by ChenYu on my RockPro64
with v5.14. Reverting the revert i.e., 2d26f6e39afb ("net: stmmac:
dwmac-rk: fix unbalanced pm_runtime_enable warnings") brings back the
network.

> Cc: Sasha as this patch has just been applied to 5.13-stable.
>
>> The symptom I see is no DHCP responses, either because the request
>> isn't getting sent over the wire, or the response isn't getting
>> received. The PHY seems to be working correctly.
>
> Unfortunately I don't have any RK3399 hardware. Is this a custom
> board/special hardware or something that is readily available in the
> shops? Maybe this is a good reason to buy a RK3399 based single-board
> computer :-)

Not sure about the other RK3399 boards but RockPro64 is easily
available.

> I am working on the RK3568 EVB1 and have not encountered faulty
> behavior. DHCP works fine and I can boot via NFS. Therefore, not sure
> whether I can be much of help in this matter, but in case you want to
> discuss this further please do not hesitate to contact me off-list.

I tried to look for the differences between RK3568 and RK3399 but the
upstream device tree doesn't seem to carry a gmac node in the device
tree for EK3568 EVB1. Do you have a pointer for the dts you're using?

Also, other than the warning "Unbalanced pm_runtime_enable!" do you
notice any other ill-effects without your patch?

If this affects all RK3399 boards as ChenYu suggests quite a few users
are going to miss the network once they upgrade.

Punit

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